Fresh fears about parent conduct at junior sport have been raised after a violent brawl broke out at a junior rugby league match between Brisbane teams Wynnum-Manly and Waterford last Friday night.

Police were called to break up fights between rival supporters and to escort the referee from the field after an under-15 match descended into violence.

Tensions rose between the two sides in a physical match, with four players sin-binned in the first half after an on-field fight.

The match ignited again in the second half, with another two players sent off for fighting. One player allegedly shoved the referee to get to a rival player, before the two players continued fighting on their way to the sideline.

The referee abandoned the match, with club officials going on to the field to try to break up the fight. Supporters then stormed on to the pitch, with around 40 fans from both sides engaging in a wild brawl.

A spectator not associated with either club, who cannot be named due to a league privacy policy, said he was shocked by the incident. "People were running down from the clubhouse fighting each other - there were ladies and mothers involved," he said. "Supporters were absolutely giving it to the referee for the send-offs. About three or four police cars arrived and they had to escort the referee off the ground."

The man said the brawl took a further turn for the worse after the match was abandoned. "In the middle of it all, the club stupidly turned the (ground) lights off," he said. "The fight then moved into the parking lot."

At least one car was damaged in the ensuing melee, with its windscreen smashed. There were concerns about alcohol fuelling the fight, as many supporters allegedly ran from the licensed clubhouse to join.

Club sporting venues are able to sell full-strength beer, wine and spirits to patrons, despite the substances being banned at all major stadiums. "It's a sad situation with under-15s being involved - it's concerning when any parents get on to the field," said Wynnum District Superintendent Jim Keogh. "Police were called to help the referee from the field. We'll be in discussions with Wynnum-Manly (rugby league) in relation to the management of what happened inside the licensed area. We'll also be canvassing if there's any (video) footage in relation to the matter."